Overview of Agrobacterium
Virulent strains of the gram-negative genus Agrobacterium harbor large plasmids known as Ti (tumor- or transformation-inducing) plasmids (pTi) in A. tumefaciens and Ri (root-inducing) plasmids (pRi) in A. rhizogenes, often classified by the opine which they catabolize or cause to be synthesized. Ti and Ri plasmids both contain DNA sequences, known as T-DNA (transferred-DNA), which in tumors are found to be integrated into the genome of the host plant. Several T-DNA genes are under control of T-DNA promoters which resemble canonical eukaryotic promoters in structure. These plasmids also carry genes outside the T-DNA region. Ti and Ri plasmids are for many purposes functionally equivalent.
Reviews of Agrobacterium-caused disease, plant transformation, genetic engineering, and gene expression include those by, or found in, Merlo, D. J. (1982) Adv. Plant Pathol. 1:139-178; Ream, L. W. and Gordon, M. P. (1982) Science 218:854-859; Bevan, M. W. and Chilton, M-D. (1982) Ann. Rev. Genet. 16:357-384; Kahl, G. and Schell, J. (1982) Molecular Biology of Plant Tumors; Barton, K. A. and Chilton, M-D. (1983) Meth. Enzymol. 101:527-539; Depicker, A. et al. (1983) in Genetic Engineering of Plants: an Agricultural Perspective, Kosuge T et al. (eds.), pp 143-176; Caplan, A. et al. (1983) Science 222:815-821; Hall, T. C. et al., European Patent application 126,546; Binns, A. N. (1984) Oxford Surveys Plant Mol. Cell Biol. 1:130-160; Hall, T. C. (1985) Oxford Surveys Plant Mol. Biol. 2:329-338; Hooykaas, P. J. J. and Schilperoort, R. A. (1985) Trends Biochem. Sci. 10:307-309; Thomas, T. L. and Hall, T. C. (1985) Bioassays 3: 149-153; Weissbach, A. and Weissbach, H. (eds.) (1986) Meth. Enzymol. 118: (see especially Rogers et al. pp 627-640); Puhler, A. (ed.) (1983) Molecular Genetics of the Bacteria-Plant Interaction; and Schilperoort, R. A. (1984) in Efficiency in Plant Breeding (Proc. 10th Congr. Eur. Assoc. Res. Plant Breeding), Lange, W. et al. (eds.), pp 251-285.